Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 72 insertions, 0 deletions

diff --git a/rust/pin-init/CONTRIBUTING.md b/rust/pin-init/CONTRIBUTING.md
new file mode 100644
index 000000000..16c899a7a
--- /dev/null
+++ b/rust/pin-init/CONTRIBUTING.md
@@ -0,0 +1,72 @@
+# Contributing to `pin-init`
+
+Thanks for showing interest in contributing to `pin-init`! This document outlines the guidelines for
+contributing to `pin-init`.
+
+All contributions are double-licensed under Apache 2.0 and MIT. You can find the respective licenses
+in the `LICENSE-APACHE` and `LICENSE-MIT` files.
+
+## Non-Code Contributions
+
+### Bug Reports
+
+For any type of bug report, please submit an issue using the bug report issue template.
+
+If the issue is a soundness issue, please privately report it as a security vulnerability via the
+GitHub web interface.
+
+### Feature Requests
+
+If you have any feature requests, please submit an issue using the feature request issue template.
+
+### Questions and Getting Help
+
+You can ask questions in the Discussions page of the GitHub repository. If you're encountering
+problems or just have questions related to `pin-init` in the Linux kernel, you can also ask your
+questions in the [Rust-for-Linux Zulip](https://rust-for-linux.zulipchat.com/) or see
+<https://rust-for-linux.com/contact>.
+
+## Contributing Code
+
+### Linux Kernel
+
+`pin-init` is used by the Linux kernel and all commits are synchronized to it. For this reason, the
+same requirements for commits apply to `pin-init`. See [the kernel's documentation] for details. The
+rest of this document will also cover some of the rules listed there and additional ones.
+
+[the kernel's documentation]: https://docs.kernel.org/process/submitting-patches.html
+
+Contributions to `pin-init` ideally go through the [GitHub repository], because that repository runs
+a CI with lots of tests not present in the kernel. However, patches are also accepted (though not
+preferred). Do note that there are some files that are only present in the GitHub repository such as
+tests, licenses and cargo related files. Making changes to them can only happen via GitHub.
+
+[GitHub repository]: https://github.com/Rust-for-Linux/pin-init
+
+### Commit Style
+
+Everything must compile without errors or warnings and all tests must pass after **every commit**.
+This is important for bisection and also required by the kernel.
+
+Each commit should be a single, logically cohesive change. Of course it's best to keep the changes
+small and digestible, but logically linked changes should be made in the same commit. For example,
+when fixing typos, create a single commit that fixes all of them instead of one commit per typo.
+
+Commits must have a meaningful commit title. Commits with changes to files in the `internal`
+directory should have a title prefixed with `internal:`. The commit message should explain the
+change and its rationale. You also have to add your `Signed-off-by` tag, see [Developer's
+Certificate of Origin]. This has to be done for both mailing list submissions as well as GitHub
+submissions.
+
+[Developer's Certificate of Origin]: https://docs.kernel.org/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
+
+Any changes made to public APIs must be documented not only in the commit message, but also in the
+`CHANGELOG.md` file. This is especially important for breaking changes, as those warrant a major
+version bump.
+
+If you make changes to the top-level crate documentation, you also need to update the `README.md`
+via `cargo rdme`.
+
+Some of these rules can be ignored if the change is done solely to files that are not present in the
+kernel version of this library. Those files are documented in the `sync-kernel.sh` script at the
+very bottom in the `--exclude` flag given to the `git am` command.